#dialog {
    position: fixed;
    left: 0;
    right: 0;
    top: 0;
    bottom: 0;
    background-color: rgba(0, 0, 0, .5);
    display: none;
}

#window {
    width: 800px;
    height: 300px;
    background-color: white;
    margin: auto;
    padding: 30px;
}